Spearhead Nanometric Field-Effect Transistor Sensors for Single-Cell Analysis.

Area of Science:

• Nanotechnology
• Biosensors
• Cellular Microenvironment Analysis

Background:

• Field-effect-transistor (FET) sensors offer potential for localized biochemical detection.
• Carbon nanoelectrodes fabricated via nanopipettes provide a versatile platform for sensor development.
• Monitoring extracellular and intracellular biochemical gradients is crucial for understanding cell biology.

Purpose of the Study:

• To develop highly localized nanometric FET sensors for real-time monitoring of pH and ATP gradients.
• To create a selective adenosine triphosphate (ATP) biosensor utilizing immobilized enzymes on a sensitive nano-FET platform.
• To investigate the application of these sensors in analyzing the microenvironment of living cells, including cancer cells and cardiomyocytes.

Main Methods:

• Fabrication of spear-shaped dual carbon nanoelectrodes using double-barrel nanopipettes.
• Deposition of electrodeposited polypyrrole (PPy) as the transistor channel material.
• Immobilization of hexokinase enzyme onto polypyrrole nano-FETs to create an ATP biosensor.

Main Results:

• The polypyrrole nano-FETs demonstrated high sensitivity to pH changes.
• The developed nano-FETs functioned as selective ATP biosensors.
• Real-time monitoring of extracellular pH and ATP gradients in the vicinity of cancer cells and cardiomyocytes was achieved.
• The spear-like design enabled highly localized detection and 3D spatial gradient mapping.

Conclusions:

• Nanometric FET sensors fabricated on carbon nanoelectrodes are effective for localized biochemical sensing.
• The PPy-based nano-FETs with immobilized hexokinase provide a sensitive and selective ATP biosensor.
• These nano-FET probes facilitate real-time, 3D monitoring of cellular microenvironment gradients and intracellular measurements.